MONDAY, May 24 (HealthDay News) -- Homeless U.S. adults are up to 10 times less likely to get the health care they need than people in the general population, a new survey reveals.

The poll results -- analyzed by researchers from both the Massachusetts General Hospital (MGH) and the Boston Healthcare for the Homeless Program -- are reported in the May issue of the American Journal of Public Health.

"Our study documents the substantial inability of homeless people to get the health care they need," study author Dr. Travis Baggett, from MGH's department of medicine, said in a news release. "Almost three-quarters of respondents had at least one type of unmet health-care need. Rates for specific services were six to 10 times higher than those seen in the general population, and being uninsured was a consistent predictor of the inability to get needed care."

The findings were drawn from an analysis of data collected by the 2003 Health Care for the Homeless (HCH) User Survey, which interviewed about 970 homeless adults at 79 clinics across the United States that receive funding from the U.S. Department of Health and Human Services.

Those polled were asked to recount any trouble they had experienced in getting health care in one of five areas over the prior year: medical or surgical care, prescription medications, mental health, vision care and dental care.

Nearly half said they had had two or more unmet needs. Specifically, nearly a third had been unable to obtain necessary medical or surgical services, while more than a third had been unable to get the prescription drugs they needed. Just over 40 percent said eyeglasses were the issue that fell through the cracks, while the same number said they had been unable to obtain dental care.

The working poor -- those that had been employed at least part time in the past year -- were less likely to get the care they needed than those who were unemployed, in part because they were less likely to have health insurance, the research team found.

Lack of health insurance or money to pay were the reasons most frequently associated with lack of care, followed by insufficent food, vision problems, and having been in foster care when young.

The study authors, who said their research likely underestimated the problem of unmet health needs, called for efforts to address the unique needs of homeless Americans and remove barriers to their health care.